TERRASTAR-D™ Precise Positioning GNSS Augmentation Service
The TERRASTAR-D™ service is a precise positioning GNSS augmentation service from Septentrio designed to deliver decimetre level position accuracy to land users globally, while providing a solution that is more resilient to satellite masking and ionospheric scintillation. The service is based around Precise Point Positioning (PPP) techniques using both GPS and GLONASS, where all GNSS system errors are removed or minimized by direct calculation, precise modeling or estimation. PPP consists of a single set of corrections to the GPS and GLONASS satellite orbits and clocks, allowing position accuracy to be maintained regardless of user location. Measurement precision is achieved by using both L1 and L2 carrier phase observations, along with C/A and P-Code measurements.